Friction facing and process of making same



Patented Sept. 4, 1923.

outrun s'raras PATENT QFFHCE.

LESTER KIRSCHBEAUN, OF CHICAGO, ILLINOIS, ASSIGNOB TO THE RAYBES'IOS COM- PANY, OF BRIDGEPCBT, CONNECTICUT, A CORPORATION OF CONNECTICUT.

FRICTION FACING AND PROCESS OF MAKING SAME.

. Hellrawlng. Application filed August 16, 1920, Serial No. 404,012. Renewed. February 13, 1922.

Serial E0. 586,348.

To all whom it may concern:

'Be it known that I, Lnsmn Kmscnnnarm, a citizen of the United States, residing in the city of Chicago, county of Cook, and State of Illinois, have invented certain new and 'useful Improvements in Friction Facings and Processes of Making Same, of which the following is a specification.

This invention relates to improvements in friction facings and process of making same and refers more particularly to a friction element such as a clutch ring adapted for usein motor cars and the like.

The object of the invention is to provide a friction facing made from relatively cheap incombustible fibre, as for example, short asbestos fibres, which facing is impregnated or saturated with a relatively cheap binder but which, nevertheless, has the required coeflicient of friction, Brinnell hardness and tensile strength.

The process may be carried out as follows: The friction facings, as for example, clutch rings, may be cut out of asbestos millboard and calendered and dried in the usual way.

These rings are then immersed in a' saturating solution. This saturating solution consists of asphalt or asphaltic oil dissolved in phenol to which may be added a thinning vehicle such aspetroleum gas oil. It may not be necessary to use pure phenol as any of the coal tar distillates, containing tar acids of this nature, may answer the purpose. The percentages of the in edients, of course, may be varied, althougg a mixture of 80% .Mexican asphalt, of less than 100 melting oint, to 20% of phenol may be used. T, e proportions will vary with the nature of the materials used and the object sought to be obtained. The friction facings may be immersed in this saturating solution for a period of several hours or until they are thoroughly impregnated and then removed. The faclngsare then either im-' A mersed in a bath of formaldehyde or subjected to the action of formaldehyde vapors, which results in forming phenol resin in the 1% may be desirable in certain cases to subsaturated element to facing in-prime condition for action by the formaldehyde. After the formaldehyde treatment, the facings are placed in an oven and subjected to a baking operation at a sufficient highly temperature to thoroughly cure and harden the facing and this treatment is continued until the facing has a tensile strength in excess of 2,000 pounds to the square inch and a Brinnell hardness in excess of 15. The extent of the baking and the temperature used will, of course, vary with the character of the phenol or coal tar distillate used and also with the charphaltic material with sufiicient phenolic condensation products to insure the desired strength and hardness. 1

The following modified method of carrying out the process may sometimes be advantageously employed. Instead of sub jectin the saturated facing to the formaldehy e treatment, this step may be obviated by incorporating in the facing an oxidizing agent, as for example, lead oxide or lead resinate.

I claim as my invention:

1. A process of making a friction facing consisting in forming a facing element from unwoven sheeted asbestos fibre, saturating said element in a solution of bituminous substance and phenol, removing the saturated element and subjecting it to the action of formaldehyde and then baking or curing the A the desired strength and hardness.

2. A process of making a friction facing consisting in formin a facing element from unwoven sheeted as estos fibre, saturating said element in a .solution of bituminous substance and-phenol, removing the'saturated elementand subjecting it to the action of formaldehyde and then baking or curing the saturated element to the desired strength and hardness and continuing said bakmg and curing until the element has a Brinnell said element in a solution of bituminous subhardness in excess of 15 and a tensile stance and phenol, removing the saturated strength exceeding 2,000 pounds to the element and subjecting it to the action of 10 square inch. I formaldehyde and cur-1n the element to the 5 3. A process of making a friction facing, desired strength and bar ess.

consisting in forming a facing element from unwoven sheeted asbestos fibre, saturating LESTER KIRSCHBRAUN. 

